U.S. patent application number 13/920848 was filed with the patent office on 2013-10-24 for method for inhibiting fouling in vapor transport system.
The applicant listed for this patent is BAKER HUGHES INCORPORATED. Invention is credited to Zhenning Gu, Bradley Harrell, Roger D. Metzler.
Application Number | 20130277606 13/920848 |
Document ID | / |
Family ID | 45466206 |
Filed Date | 2013-10-24 |
United States Patent
Application |
20130277606 |
Kind Code |
A1 |
Metzler; Roger D. ; et
al. |
October 24, 2013 |
METHOD FOR INHIBITING FOULING IN VAPOR TRANSPORT SYSTEM
Abstract
Elimination and/or mitigation of fouling in a vapor transport
systems, such as vent lines and scrubber feed lines may be
accomplished using an antifouling additive. The method for
employing the antifouling additive includes introducing into the
vapor transport system an additive including a polar solvent and
corrosion inhibitor wherein: the vapor transport system is
substantially water free; the vapor transport system is used to
transport acidic materials; the additive is a liquid at vapor
transport system operating conditions; and the additive is stable
at the vapor transport system operating conditions.
Inventors: |
Metzler; Roger D.; (Sugar
Land, TX) ; Gu; Zhenning; (Sugar Land, TX) ;
Harrell; Bradley; (Pearland, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BAKER HUGHES INCORPORATED |
HOUSTON |
TX |
US |
|
|
Family ID: |
45466206 |
Appl. No.: |
13/920848 |
Filed: |
June 18, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13169572 |
Jun 27, 2011 |
8465640 |
|
|
13920848 |
|
|
|
|
Current U.S.
Class: |
252/182.29 |
Current CPC
Class: |
C01B 7/0706 20130101;
C23F 11/02 20130101; F28F 19/00 20130101; C23F 11/04 20130101; C23F
11/00 20130101 |
Class at
Publication: |
252/182.29 |
International
Class: |
C01B 7/07 20060101
C01B007/07 |
Claims
1. A method for the production of chemical compositions comprising
transporting anhydrous vapor through metal pipes and introducing
into the vapor transport system an additive comprising a polar
solvent and corrosion inhibitor wherein: the vapor transport system
is substantially water free; the vapor transport system is used to
transport at least one acidic material; the additive is a liquid at
vapor transport system operating conditions; and the additive is
stable at the vapor transport system operating conditions; wherein
the polar solvent is: an aliphatic amide selected from the group
consisting of N, N-dimethylacrylamide, N-isopropylacrylamide,
N-methacrylamide, N,N-diethylacrylamide, and combinations thereof;
or the polar solvent is N-methyl-2-pyrrolidone.
2. The method of claim 1 wherein the at least one acidic material
is also a source of fouling
3. The method of claim 1 wherein the additive is introduced into
the vapor transport system continuously.
4. The method of claim 3 wherein the continuous introduction of the
additive functions to prevent or mitigate deposition of fouling
deposits.
5. The method of claim 1 wherein the additive is introduced into
the vapor transport system intermittently.
6. The method of claim 5 wherein the intermittent introduction of
the additive functions to at least partially remove existing
fouling deposits.
7. A method for the production of chemical compositions comprising
transporting anhydrous vapor through metal pipes and introducing
into the vapor transport system an additive comprising a polar
solvent and corrosion inhibitor wherein: the vapor transport system
is substantially water free; the vapor transport system is used to
transport at least one acidic material; the additive is a liquid at
vapor transport system operating conditions; and the additive is
stable at the vapor transport system operating conditions; wherein
the corrosion inhibitor is a quaternary amine selected from the
group consisting of quaternized alkylpyridines, quaternized fatty
amines, and combinations thereof.
8. The method of claim 7 wherein the at least one acidic material
is also a source of fouling
9. The method of claim 7 wherein the additive is introduced into
the vapor transport system continuously.
10. The method of claim 9 wherein the continuous introduction of
the additive functions to prevent or mitigate deposition of fouling
deposits.
11. The method of claim 7 wherein the additive is introduced into
the vapor transport system intermittently.
12. The method of claim 11 wherein the intermittent introduction of
the additive functions to at least partially remove existing
fouling deposits.
13. A method for the production of chemical compositions comprising
transporting anhydrous vapor through metal pipes and introducing
into the vapor transport system an additive comprising a polar
solvent and corrosion inhibitor wherein: the vapor transport system
is substantially water free; the vapor transport system is used to
transport at least one acidic material; the additive is a liquid at
vapor transport system operating conditions; and the additive is
stable at the vapor transport system operating conditions.
14. The method of claim 13 wherein the at least one acidic material
is also a source of fouling
15. The method of claim 13 wherein the additive is introduced into
the vapor transport system continuously.
16. The method of claim 15 wherein the continuous introduction of
the additive functions to prevent or mitigate deposition of fouling
deposits.
17. The method of claim 13 wherein the additive is introduced into
the vapor transport system intermittently.
18. The method of claim 17 wherein the intermittent introduction of
the additive functions to at least partially remove existing
fouling deposits.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. Pat. No. 8,465,640,
filed Jun. 27, 2011, which claims priority from U.S. Provisional
Patent Application Ser. No. 61/363,928 filed on Jul. 13, 2010, the
disclosures of which are incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a method for inhibiting fouling in
vapor transport systems. The invention particularly relates to the
use of additives for inhibiting fouling in vapor transport
systems.
[0004] 2. Background of the Art
[0005] Acidic materials may be difficult to use in the manufacture
of chemicals and other products. Unless kept anhydrous, these
materials may be very corrosive and thus requiring the use of
exotic, fragile, and/or very expensive materials in the
construction of units employing them. For example, anhydrous HCl is
relatively non-corrosive, but introduce even a small amount of
water or other compound that can form a hydronium ion, or its
analog, and use of glass lined pipe may be required for safe
handling.
[0006] This problem is not limited to literal acids, but also
extends to compounds that can generate acids. One example of this
is anhydrides. Unsaturated anhydrides are common components of, for
example, copolymers. In an anhydrous environment, these compounds
are comparatively stable and non-corrosive. In the presence of
water however, they are quickly converted to acids and may be very
corrosive.
[0007] It is often desirable to handle these compounds as vapor.
One problem with handling these vapors is that solids may form and
be deposited on the surfaces of the systems used to transport the
vapor. If not corrected, this can result in plugging. The foulants
are often removed mechanically which may cause substantial losses
of productivity.
[0008] Care should be employed that solutions to problems within a
vapor transport system not cause new problems downstream. For
example, in many processes utilizing a vapor transport system it
may be desirable to scrub the vapor stream. Gas/Vapor Scrubbers are
devices used for separating components of a gas admixture. In some
embodiments, these devices are used to "purify" gasses/vapors or,
stated in the alternative, remove undesirable components from a
gas/vapor stream. For example, primitive scrubbers have been used
since the inception of submarine warfare to remove carbon dioxide
from the air supply in the submarine.
[0009] More recently, gas scrubbers have proven to be essential in
many industries. For example, Gas Scrubbers are used to prevent
pollution from the burning of coal during power generation. Gas
Scrubbers are also used to remove undesirable components from
process gas streams during the production of chemicals, metals and
devices such as semiconductors and the like.
[0010] Care should be taken to avoid solutions to plugging problems
in a vapor transport system that will result in problems with
downstream scrubbers.
SUMMARY OF THE INVENTION
[0011] In one aspect, the invention is a method for the prevention
or mitigation of fouling in vapor transport systems comprising
introducing into the vapor transport system an additive comprising
a polar solvent and corrosion inhibitor wherein: the vapor
transport system is substantially water free; the vapor transport
system is used to transport acidic materials; the additive is a
liquid at vapor transport system operating conditions; and the
additive is stable at the vapor transport system operating
conditions.
[0012] In another aspect, the invention is a method for the
production of chemical compositions comprising transporting
anhydrous vapor through metal pipes and introducing therein an
additive comprising a polar solvent and corrosion inhibitor
wherein: the vapor transport system is substantially water free;
the vapor transport system is used to transport acidic materials;
the additive is a liquid at vapor transport system operating
conditions; and the additive is stable at the vapor transport
system operating conditions.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] One embodiment of the invention is a method for the
prevention or mitigation of fouling in vapor transport systems
comprising introducing into a vapor transport system an additive
comprising a polar solvent and corrosion inhibitor. Examples of
polar solvent useful with the methods of the application may
include, but are not limited to: aliphatic alcohols, aliphatic
amides and lactams, aliphatic ethers, and combinations thereof.
When the polar solvent is an aliphatic alcohol, in some embodiments
it may have from 2 to 14 carbons. In some embodiments the aliphatic
alcohols may be selected from the group consisting of ethanol,
n-propanol, isopropanol, n-butanol, tert-butanol, isobutanol, and
mixtures thereof. In other embodiments, especially higher
temperature applications, the aliphatic alcohol may be selected
from the group consisting of n-pentanol, n-hexanol, n-heptanol,
n-octanol, n-decanol, n-dodecanol (lauryl alcohol), 2-ethylhexanol,
stearyl alcohol, cetyl alcohol, lauryl alcohol, cyclopentanol,
cyclohexanol, cyclooctanol, cyclododecanol, and combinations
thereof. Any aliphatic alcohol which is liquid and stable at the
conditions within the vapor transport system may be used with the
methods of the disclosure.
[0014] When the polar solvent is an aliphatic amide, in some
embodiments, it may be selected from the group consisting of maleic
amides, fumaric amides, itaconic amides, citraconic amides and
acrylamides. In some embodiments, the aliphatic amide may be N,
N-dimethylacrylamide and in other embodiments, it may be
N-isopropylacrylamide or N-methacrylamide. In still other
embodiments, the aliphatic amide may be N, N-diethylacrylamide.
When a lactam is used, the lactam may be N-methyl-2-pyrrolidone.
Any aliphatic amide which is liquid and stable at the conditions
within the vapor transport system may be used with the methods of
the disclosure.
[0015] When the polar solvent is an aliphatic ether, in some
embodiments, it may be selected from the group consisting of
diethyl ether, diisopropyl ether and t-butylmethyl ether
combinations thereof. In other embodiments, the aliphatic either
may be selected from the group consisting of n-propyl ether,
n-butyl ether, n-amyl ether, isobutyl ether, isoamyl and ether and
methyl butyl ether. Any aliphatic ether which is liquid and stable
at the conditions within the vapor transport system may be used
with the methods of the disclosure.
[0016] Polar solvents having both ether and alcohol functionalities
may also be used. For example, in some embodiments of the
disclosure, ethylene glycol butyl ether may also be used as the
polar solvent.
[0017] Corrosion inhibitors that may be used with the methods of
the disclosure include, but are not limited to, imidazoles and
their derivatives, quaternary amines, acetylenic alcohols,
pyrimidines, pyridazines, amides, carbamates, and their derivatives
and combinations thereof. When the corrosion inhibitor is an
imidazole, in some embodiments, it may be selected from the group
consisting of benzimidazole, benzothiazole, bifonazole,
butaconazole nitrate, clotrimazole, croconazole, eberconazole,
econazole, elubiol, fenticonazole, fluconazole, flutimazole,
isoconazole, lanoconazole, metronidazole, miconazole, neticonazole,
omoconazole, oxiconazole nitrate, sertaconazole, sulconazole
nitrate, tioconazole, thiazoles, and triazoles such as terconazole
and itraconazole, and mixtures thereof. In other embodiments, the
imidazoles may be selected from the group consisting of
1-benzyl-2-methylimidazole, 2-methylimidazole and
2-butylimidazole.
[0018] Imidazole derivatives that may be used with the methods of
the disclosure include any aliphatic substituted imidazole. Any
imidazoles or imidazole derivatives that are liquid at the
operating conditions of the vapor transport system may be used.
[0019] When the corrosion inhibitor is a quaternary amine, it may
be selected from the group consisting of quaternary ammonium
compounds and quaternary amines having from about 2 to about 30
carbons. Exemplary quaternary amines useful with the method of the
application include, but are not limited to, quaternized
alkylpyridines, quaternized fatty amines. Any quaternary amine
which is liquid and stable at the conditions within the vapor
transport system may be used with the methods of the
disclosure.
[0020] When the corrosion inhibitor is an acetylenic alcohol, the
acetylenic alcohol may be selected from the group consisting of
such alcohols having from about 3-16 carbon atoms. In some
embodiments, ethyl octynol, propargyl alcohol, hexynol may be used
as the corrosion inhibitor. In other embodiments, methyl butynol,
methyl pentynol, hexynol, ethyl octynol, propargyl alcohol, benzyl
butynol, naphthalyl butynol, and the like may be used. Any
acetylenic alcohol which is liquid and stable at the conditions
within the vapor transport system may be used with the methods of
the disclosure.
[0021] When the corrosion inhibitor is a pyrimidine, it may be
substituted or unsubstituted. When substituted, is some
applications, it may be substituted with oleic, naphthenic, or
fatty type alkyl groups. For example, coco or tall oil alkyl
groups. Amides and carbamates may be similarly substituted. In some
embodiments, these compounds may have more than a single
substitution.
[0022] The corrosion inhibitors useful with some embodiments of the
disclosure may have more than one functional group. For example, in
some embodiments, the corrosion inhibitor may have both imidazole
and amide functionality. In other embodiments, the corrosion
inhibitor may have other combinations. Any polyfunctional corrosion
inhibitor known to those of ordinary skill in the art may be used
with the method of the application.
[0023] In the methods of the disclosure, the vapor transport system
is substantially water free. For the purposes of this application,
the term "substantially water free" means that the vapor being
transported within the vapor transport system has less than 2000
ppm of condensed water present.
[0024] The additives of the application have at least two
components, a polar solvent and a corrosion inhibitor. These
compounds are present in a ratio to each other of from about 1:99
to about 99:1 in some embodiments and from about 1:9 to about 9:1
in other embodiments. When other components are present, such as a
foulant morphology modifier, the concentration of the polar solvent
and corrosion inhibitor may be from about 1% to about 99%.
[0025] In the practice of the invention, the vapor transport system
is used to transport acidic materials. For the purposes of this
application, the term "acidic materials" means compounds capable of
forming sufficient hydronium ions in the presence of electrolyte to
be corrosive to most mild steel. In some applications, the acidic
materials will be the source of fouling. For example, where a
copolymer is being prepared with maleic anhydride and the maleic
anhydride is plugging a vapor recovery system, maleic acid and
anhydride is both the foulant and the acid material transported
within the vapor transport system.
[0026] In contrast, where butene is being transported with an acid
material such as anhydrous HCl, and the butene is polymerizing to
produce polybutene which is fouling the system, then the HCl is the
acid material, but in this embodiment, the polybutene is the
foulant.
[0027] As already stated, HCl; butene, and maleic anhydride may be
components within a vapor transport system as practiced by the
methods of the application. Other components that may also be used
with the methods of the application include, but are not limited to
2, 5-furandione, phthalic anhydride, and the like.
[0028] In the methods of the application, the additive is a liquid
at vapor transport system operating conditions. For the purposes of
the application, this means that the additive, when added to the
vapor transport system, is a liquid and below its boiling point
although, like any liquid, the additive may have a vapor pressure
and evaporate over time.
[0029] The additives useful with the methods of the applications
are stable at the vapor transport system operating conditions. In
the practice of these methods, the additive does not decompose and
remains effective for, in some embodiments, at least 24 hours under
the conditions of the vapor transport system. Since conditions will
vary depending upon the application being served by the vapor
transport system, an operator of such a system will well know how
to specify/select the additive that meets the needs of his
particular application. For example, a high temperature application
will require a polar solvent and corrosion inhibitor that have a
boiling point greater than the operational temperature of the
system. In addition to temperature, other conditions that may be
present in the vapor transport system (and in some embodiments
controllable by an operator thereof) include pressure, vapor flow
rates, and the selection of components present in the vapor being
transported.
[0030] While not wishing to be bound by any theory, it is
never-the-less believed that employing a polar solvent in an acidic
vapor transport system, while effective at reducing fouling, will
result in corrosion due to the interaction of the acidic materials
and the solvent and any latent water that may be present in the
solvent. This is, of course, undesirable. The synergistic
combination of the polar solvent and the corrosion inhibitor allow
for the prevention or mitigation of fouling without excessive
corrosion within the system.
[0031] In addition to the other properties, the additives used with
the methods of the disclosure do not act as surfactants or
otherwise cause scrubber failures. Scrubber failures may have
safety and environmental consequences. At the very least they can
cause loss of productivity.
[0032] The additives of the application are desirably introduced
into the vapor transport systems at an effective concentration.
Those of ordinary skill in the art of running such units are well
versed in determining the effective concentration of additives to
use in their equipment. Such concentrations are dictated by the
operational conditions of the equipment. For example in some
application, the additives are introduced at a rate of 5000 ppm. In
other applications, the additives are introduced at a rate of 50
ppm.
[0033] The additives of the application may be introduced into
vapor transport systems using any process known to be useful to
those of ordinary skill in the art of running such systems. Methods
of application may include online cleanup of existing deposition
material via intermittent additive injection, and prevention of
deposition via continuous additive injection.
[0034] In addition to the additive components already described,
the additives of the disclosure may include other compounds known
to be useful. Any compound that does not have an undesirable
interaction with the additive's ability to prevent fouling may be
used with at least some embodiment of the method of the
invention.
[0035] Current solutions to the deposition problem include the use
of mechanical cleaning that requires process shutdown limiting
plant production capacity. Application of the additive may reduce
or eliminate mechanical cleaning, system down time, and permit
increased operational utilization thus increasing production
capacity.
EXAMPLES
[0036] The following examples are provided to illustrate the
present invention. The examples are not intended to limit the scope
of the present invention and they should not be so interpreted.
Amounts are in weight parts or weight percentages unless otherwise
indicated.
Example 1
[0037] 74 parts N-methyl-2-pyrrolidone, 20 parts ethylene glycol
butyl ether, 3 parts alkylated succinic acid, and 3 parts heavy
aromatic solvent are admixed to form a solution. Lab testing was
conducted by adding a typical vent line deposit sample composed of
poly-butene and 2,5-furandione and their derivatives, into the
additive at a weight ratio of one part deposit per ten parts of
additive. A test vial containing the mixture was kept isothermal in
a water bath heated to 170.degree. F. No agitation was applied to
the mixture. Within 30 minutes, the deposit was completely
disintegrated, converted into "flow-able" form and suspended in the
bulk additive phase.
[0038] The same test was repeated in a mixture of the additive and
concentrated hydrochloric acid (.about.37%) to evaluate the
performance in presence of hydrogen chloride. Within 30 minutes,
the deposit was completely dissolved. This test confirmed the
efficacy of the additive in acidic environment.
[0039] Emulsifying tendency of the additive formulation in
saturated hydrochloric acid was also tested. No emulsion formation
was observed in the test.
Example 2
[0040] The corrosion potential of the additive formulations on
Monel 400 metallurgy in presence of anhydrous hydrogen chloride was
determined. The testing procedure included purging HCl (g) through
the test liquid to saturation, suspending a Monel 400 coupon into
the test liquid, sealing the test sample container and settling it
at 170.degree. F. for an extended period of time. The corrosion
rate is calculated based on weight loss of the coupon through the
test due to corrosion. Without an effective corrosion inhibitor,
the corrosion rate of the additive formulation was 84 MPY on Monel
400. With an effective corrosion inhibitor formulated into the
additive, the corrosion rate was tested to be 17 MPY, an 80%
reduction.
* * * * *